Asthma link to antibiotics

Children given antibiotics during the first six months of life are up to 11 times more likely to develop allergies and asthma, warn experts.

Early exposure to the drugs dramatically increases the risk of triggering common allergies including pets, dust mites and hay fever, a study found.

Experts discovered the threat rose with each course of antibiotics given to an infant and for those whose mothers had allergies.

The highest risk was for babies given a broad-spectrum antibiotic, which includes penicillin, while breastfeeding for more than four months also heightened the chances of allergic reaction.

Because antibiotics wipe out both good and bad bugs in the gut, it is thought they may disturb the body's immune programming in the crucial early months of life.

The findings by a team at the Henry Ford Hospital, in Detroit, are unveiled as scientists and child health experts become increasingly concerned over the rising level of medical problems linked to allergic reactions over the last 25 years.

More than a million British children have been diagnosed with asthma, while many thousands more have wheezing problems, allergies and skin rashes caused by eczema.

Senior researcher Dr Christine Cole Johnson said the latest findings were a 'new warning' over the need to restrict the use of antibiotics.

Doctors were now aware of the hazards of antibiotic resistance in fuelling the growth of superbugs, and were cutting down on their use.

'I'm not suggesting children shouldn't receive antibiotics,' said Dr Johnson.

'But I believe we need to be more prudent in prescribing them at such an early age.

'In the past many of the drugs were prescribed unnecessarily, especially for viral infections such as colds or flu when they would have had no effect anyway.'

Researchers studied 448 children from birth to the age of seven - 50 per cent of whom had received antibiotics in the first six months of life. Half had been given more than one course.

The team took into account the type of antibiotic prescribed, whether the children had pets, the period of breastfeeding and the mother's history of allergies.

They found that by the age of seven, youngsters who had been given at least one antibiotic in the first six months of life were 1.5 times more likely to develop allergies than those who did not have drugs and 2.5 times more likely to develop asthma.

The risk was even higher for children who lived with fewer than two pets - thought to protect youngsters against developing allergies.

Children on antibiotics whose mothers suffered from allergies had double the risk of developing them, and those breast-fed for more than four months were three times more at risk.

The risk was a massive 11-fold for children who received broad-spectrum antibiotics, were breast-fed for four months and did not have any pets, Dr Johnson told the European Respiratory Society's annual conference in Vienna yesterday.

She said 'The results of our prospective birth study suggest that antibiotic use is a risk factor for allergy in children, particularly those who already have other risk factors.

'What's more, the increased risk is proportionate to the number of courses of antibiotics given.

'Three courses in the first six months mean that the risk is multiplied by five for a child who did not have much contact with animals and was breast-fed for a long time.'

Antibiotics had an extra damaging effect in children who had inherited a predisposition to allergies or had not benefited from protective factors.

Dr Johnson, a senior epidemiologist, said the most likely reason was changes in bacteria in the gut.

A spokesman for the National Asthma Campaign said: 'Studies looking at the relationship between the development of asthma and allergies in children who have received antibiotics at an early age, as well as the effects of when women have taken antiobiotics while pregnant, have been inconclusive.

'Whilst this is an interesting study, further research is needed to understand the complexities of the relationship between these factors.'